Papers by Keyword: Corona Poling

Abstract: The study explores the integration of additive manufacturing for the development of 4D-printed piezopolymer metamaterials, aiming to create dynamic, multifunctional structures capable of distributed sensing and energy harvesting. The focus is on Polyvinylidene fluoride (PVDF), a partially fluorinated polymer renowned for its strong electromechanical coupling, specifically within its polar β-phase. To harness these properties, three distinct experimental strategies were evaluated for integrating PVDF with conductive electrodes necessary for electrical poling: direct 3D printing with manually applied silver paste, printing directly onto pre-integrated aluminium foil substrates, and a novel chemical solvent-based deposition using a DMF/acetone mixture. While high-precision inkjet printing was initially tested for electrode deposition, it demonstrated significant limitations in scalability, throughput, and durability, particularly suffering from structural degradation during the post-poling silicon oil removal process. Consequently, the study advocates for a robust, hybrid multi-material extrusion platform. This approach will enable the simultaneous, monolithic deposition of structural PVDF thermoplastics and highly conductive thixotropic inks.

Abstract: Hybrid organic-inorganic films are attractive materials for an alternative manufacture of photonic devices based on non-linear second-order optical processes. However, their efficiency and stability, closely related to their chromophores non-centrosymmetric orientation, still need some improvements. The use of nanostructures in this kind of materials gives place to a change in the chromophores surrounding medium; it can be used to improve the efficiency and the stability of the chromophores orientation in the films. In this work we show that some nanostructures are able to improve significantly the organic-inorganic SiO₂ films second-order non-linear optical responses. Two kinds of nanostructures were studied: some nanostructures were just immersed, but the other ones were spontaneously induced in the films. The immersed nanostructures were multi-walled carbon nanotubes and the spontaneously induced nanostructures were formed in the films by means of surfactants self-assembly. The films were synthesized by the sol-gel method and all of the films were doped with Disperse Red 1 (DR1) dipolar chromophores. The induced nanostructures were lamellar and hexagonal long-range ordered nanostructures, detected by X-ray diffraction (XRD). The second-order non-linear optical properties of the films were studied in resonance through Corona poling assisted second harmonic generation. The results show significant improvements, for some kinds of nanostructures, in the non-linear optical responses of the films. In particular, those films containing Triton X-100 showed, at a poling temperature of 120°C, an improved second-order non-linear coefficient d₃₃ with respect to equivalent non-nanostructured films; the d₃₃ value of those films, determined by the Maker fringes technique, was equal to 21.4 pm/V.

Abstract: We report the effect of electric field on third order nonlinear optical properties of Hydrazone (Hz) doped Polymethyl methacrylate (PMMA) films. The films were prepared by solution casting method. Poling of films was done by corona discharge. Single beam Z-scan technique with 7ns Nd: YAG laser pulses at 532nm were employed for the measurements. Third order susceptibility of films was measured with an emphasis on the applied electric field. We also demonstrated the second harmonic generation in the corona poled films.

Abstract: The kinetics of the orientation of Disperse Red 1 (DR1) molecules embedded in nanostructured Polymethylmetacrylate (PMMA) films was studied under the effect of an intense constant electric poling field. The changes in the orientation distribution of the DR1 molecules were followed by Second Harmonic Generation (SHG) measurements. The SHG signal was recorded as function of time at three different temperatures. We focused on both, the signal increases under the presence of the poling field and the signal decays without the poling field. The studied PMMA films were nanostructured by the incorporation of ionic surfactants as the Sodium Dodecyl Sulfate (SDS) and the Cetyl Trimethyl Ammonium Bromide (CTAB) during their preparation. The kinds of nanostructures obtained in the films were determined by means of X-ray diffraction (XRD) measurements. Substantial differences in signal intensity and in growth and decay rates between amorphous and nanostructured films were found.